Conventionally there are two basic methods for controlling write accesses to a shared resource such that two concurrent processes run by different computers do not corrupt data stored in the shared resource. A first of these two methods is a token-passing ring method, and the second is a client-server model of enforced resource sharing.
In the token-passing ring method, access to a shared resource is gained by a computer by putting that computer's signature on a token, and passing that token to the next host in the ring. Passing the token with the signature tells the next host that “I want to reserve this resource.” The token is typically passed to a plurality of host computers. Each host that receives the token must sign off on the token before the computer that originated the token can access the resource. In this method, each host must allow the originating computer to have access to the resource before the originating computer will access the resource.
In the client-server model, a single resource dispenser tracks which host computer may have access to the resource at a given time. Typically, each host computer sharing the resource must send a request to the resource dispenser and receive an acknowledgement that they may access the resource before they may access the resource.
Both the token-ring and the client-server model require a general purpose interface and use a general protocol for passing tokens or requests, and the entire network must be configured by a system administrator before a shared resource may be shared.
There is a need to improve methods for a plurality of host computers that share a shared resource in a way that minimizes administration costs.